Fix java validatesdistrolesscontainer dataflow workflow (#33245)

* Set testJavaVersion in each run

* Modify trigger file

* Add dockerTag

.github/trigger_files/beam_PostCommit_Java_ValidatesDistrolessContainer_Dataflow.json

@@ -1,4 +1,4 @@
 {
   "comment": "Modify this file in a trivial way to cause this test suite to run",
-  "modification": 1
+  "modification": 2
 }

.github/workflows/beam_PostCommit_Java_ValidatesDistrolessContainer_Dataflow.yml

@@ -88,10 +88,17 @@ jobs:
           gcloud auth configure-docker us.gcr.io --quiet
           gcloud auth configure-docker gcr.io --quiet
           gcloud auth configure-docker us-central1-docker.pkg.dev --quiet
-      - name: run validatesDistrolessContainer script
+      - name: run validatesDistrolessContainer script (Java 17)
         uses: ./.github/actions/gradle-command-self-hosted-action
         with:
           gradle-command: :runners:google-cloud-dataflow-java:examplesJavaRunnerV2IntegrationTestDistroless
+          arguments: '-PtestJavaVersion=java17 -PdockerTag=$(date +%s)'
+          max-workers: 12
+      - name: run validatesDistrolessContainer script (Java 21)
+        uses: ./.github/actions/gradle-command-self-hosted-action
+        with:
+          gradle-command: :runners:google-cloud-dataflow-java:examplesJavaRunnerV2IntegrationTestDistroless
+          arguments: '-PtestJavaVersion=java21 -PdockerTag=$(date +%s)'
           max-workers: 12
       - name: Archive JUnit Test Results
         uses: actions/upload-artifact@v4